This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. TFIIB plays a key role in RNA polymerase II mediated transcriptional initiation. TFIIB functions as a bridge that links together the RNA polymerase II and promoter and orchestrates the accurate start site selection. TFIIB, composed of 328 amino acids, can be divided into several independently folded domains including an N-terminal Zinc-ribbon domain, a B-finger domain, a Linker domain and a C-terminal Core domain. Biochemical data have implicated an conformational change before and after promoter binding. In our RNA polymerase II - TFIIB crystal structure, we observed a conformation state that is similar to the promoter-bound state even in absence of promoter in the crystal structure. We reason that the crystallization condition may account for the conformational change that is normally accomplished through promoter binding. So we propose to investigate the conformation states of TFIIB under different buffer conditions and to compare them with the promoter-bound conformation of TFIIB.